In the known forms of binocular viewing devices for viewing image converters, image intensifiers, or fluorescent screens, there are usually two separate optical magnification systems, one for each eye of the user, just as in the case of ordinary binoculars or field glasses. Accordingly, the prior art devices are bulky and heavy, which is particularly undesirable if the device is to be held in the hand of the user.
An object of the present invention is to provide a device which is both compact and light in weight, enabling the device to be held easily in the hand of the user. In furtherance of this object, the device of the present invention has only a single optical magnification system, rather than two systems, and the lens elements of this magnification system are formed of material having the lowest possible density consistent with the desired optical properties. At the rear end of the optical system (the end toward the eyes of the user) there are two rhombic prisms behind the last lens surface of the system, which effect a pupillary division or spread the light beam to increase the interpupillary distance to match or approximately match that of the eyes of the user or observer.